Surface element for friction increase as well as objects provided with said surface element

ABSTRACT

A surface element ( 1 ) for friction increase comprises a lying portion ( 2 ) defining a reference surface, and engagement means ( 3 ) that can be extended and/or recessed relative to the reference surface and is suitable for interfacing with corresponding engagement means of a faced surface element for friction increase; the surface element further comprises a predetermined number of clusters ( 4 ) of the engagement means defined by respective confining edges ( 4   a ) and distributed on the lying portion, and in each of these clusters the engagement means is disposed along directrices ( 4   b ) having at least one predetermined curvature ( 4   c ) and one corresponding centre of curvature, centres of curvature of directrices belonging to clusters separated from each other not being coincident.

The present invention relates to a surface element having a preferably planar configuration and any type of confining profile, to be used for increasing sliding friction to an important degree under conditions of mutual interfacing and contact with an analogous surface element.

It is known that in many handling operations or operations for static side-by-side arrangement/piling of objects, a fundamental “cohesion” between the objects themselves is required to be obtained, as said objects must not be able to move relative to each other: for instance, let us think of the necessity to keep two furnishings in steady side-by-side relationship or to the necessity to pile up and/or dispose different packages side by side inside a warehouse or a loading compartment of a vehicle or a container.

In many situations similar to the just described ones, interposition of additional constraints between at least two objects appear to be rather arduous and/or too much expensive in terms of both the required additional expenses and the necessary resources or time (as it may happen, for example, if adhesive means or mechanical surface constraints are wished to be installed on the contacting faces of the different objects).

A particular technical field wherein generation of strong surface friction is required (and therefore constraining reactions counteracting relative sliding along the surfaces in mutual contact) is that in which the so-called package clamping operations take place: in this sector in fact multiple packing of objects is provided in which the packs are disposed side by side along substantially horizontal arrangement directions, and are then lifted (and handled) through special handling trucks having substantially flat gripping jaws such disposed as to exert pressure on the side walls of the object placed at the ends of the (horizontal) lines defining the multiple packing.

The gripping jaws of the handlers adapted to carry out clamping are therefore actively pressed on the side walls of the objects, so that in the whole packing, inner pressures are created also on the (usually lateral and vertical) faces of the innermost objects; as a result of these pressures, arising of sliding friction occurs that prevents the objects from slipping away and therefore allows the whole multiple packing to be maintained unitary.

The above illustrated situations have different drawbacks, above all connected with the requirement of generating a high sliding friction in opposition to the technical condition that too strong axial compression has not to be induced.

In particular, as to the clamping operations, it is suitable not to go beyond predetermined critical lateral/axial compression values because in this case generation of high sliding friction surely would occur, but at the same time there would also be a high incidence of damages to the objects that should be sized in an overabundant manner in order to resist lateral compression (otherwise they would run the risk of being submitted to structural crushing/yielding).

Should not be possible or convenient to oversize the objects contained in the packages in order to resist the just mentioned lateral compression, a further drawback appears in the known art; in fact, if the packed objects are not able to “autonomously” resist compression, it is necessary to oversize the package itself, for instance with addition of inner struts (typically of wood) that take up useful stowage space and increase bulkiness and overall costs.

Therefore, in the situations where the lateral/axial pressure is intrinsically very low or zero (for example let us think of two pieces of furniture placed in mutual contact in the middle of an environment but not pushed against each other or to the multiple packing of containers left “at rest” in a warehouse), the hitherto known means for increase of the sliding friction appears to be unsatisfactory beyond a given performance level, because in any case some non-negligible pressure value or the intervention of additional constraint means is required, such as adhesives or fastening straps, which will bring about an increase in costs and overall dimensions, and also (depending on the contexts) worsening of the aesthetic qualities and/or elimination of the possibility of carrying out movements of the objects separated from each other.

Still as regards insufficient sliding-friction reactions between objects or packages of known type disposed side by side or stacked up, it is possible to see that in case of particular stresses (such as some types of undulatory movements generated by seismic phenomena, for example), even objects of relatively high weight cannot succeed in ensuring sufficient sliding-friction reactions on their faces in mutual contact, and this represents a further factor of risk for the safety of the environment where these objects are.

Going back, on the contrary, to the drawbacks that can be found in the clamping operations, it has to be noted that these operations usually are not implemented with a very accurate positioning degree as regards the objects constituting the multiple packing; when the objects to be put side by side and axially/laterally pressed are not in perfect alignment, through use of (lateral) friction-increasing means of known type, relative “adjustment” motions can in any case take place, which motions greatly increase the possibility of putting the line of application of the clamping pressure of the handler jaws out of alignment; this misalignment can lead to damages to the objects or can even result in a loss of coherence/integrity of the packing, with possible risks of losing the load being handled and generating accidents and/or further damages to the objects.

Accordingly, the present invention aims at conceiving a surface element for friction increase that is able to obviate the above mentioned limits.

Mainly, it is an aim of the present invention to conceive a surface element that can increase the sliding friction between two contacting surfaces in a much greater manner, even when the lateral or vertical crushing pressure acting on the surfaces themselves has particularly low or zero values.

The present invention further aims at conceiving a surface element for friction increase capable of reducing and preferably eliminating as much as possible, any amount and/or relative-sliding direction between two mutually facing/superposed objects in contact along at least one face, both under movement/handling conditions (such as for example during a manoeuvring operation based on clamping) and under piling and/or side-by-side-arrangement conditions in static or moving environments.

Moreover, the present invention aims at conceiving a surface element for friction increase that can be made both as an autonomous intermediate element associable in any manner with at least one face of at least one object that, as an integral part of more complicated objects such as packages (preferably although not in a limiting sense, of the “reusable” or “returnable” type) or as any other object, is required to be positioned or moved in side-by-side or piled-up relationship with at least another similar object, and preferably provided with another face having the same features.

It is also an aim of the present invention to carry out a surface element for friction increase ensuring an easy and quick reversibility of the facing and contact of the faces along which the sliding friction is to be generated; in other words the present invention aims at conceiving a surface element for friction increase that enables an engagement of the reversible type at least along a direction of mutual facing/approaching, generating an important (or in other words rather high) value of coplanar sliding friction between the faces, only when the latter really touch each other.

The technical task mentioned and the aims specified are substantially achieved by a surface element for friction increase having the features set out in one or more of the appended claims.

Description of a preferred but not exclusive embodiment of a surface element for friction increase is now given by way of non-limiting example according to the invention, illustrated in the accompanying drawings, in which:

FIG. 1 is a diagrammatic plan view of a first embodiment of the surface element for friction increase according to the invention;

FIG. 2 is a diagrammatic plan view of a second embodiment of the surface element for friction increase according to the invention;

FIG. 3 is a diagrammatic plan view of a third embodiment of the surface element for friction increase according to the invention;

FIG. 4 is a diagrammatic plan view of a fourth embodiment of the surface element for friction increase according to the invention; and

FIG. 5 is a perspective view of a package of the “reusable” or “returnable” type having at least one face entirely provided with the surface element seen in FIG. 1; and

FIGS. 6, 7 and 8 show perspective views of packages of the conventional type (for instance a paperboard box) relatively disposed in different space situations and respectively having at least one face entirely provided with the surface element seen in FIG. 1.

With reference to the accompanying drawings, the surface element for friction increase according to the present invention is adapted to perform its main function being coupled with at least another surface element having at least one protrusion and/or at least one recess formed in its surface; the surface element according to the invention has been identified with reference numeral 1 and substantially comprises a lying portion 2 (generally extending in a plane, but if necessary also extending in space on a polygonal and/or curved surface) which in turn is bounded by a predetermined number of perimetral edges 2 a sequentially connected to each other.

In terms of geometry and structure, the lying portion defines a reference surface 2 b: relative to such a surface, suitable engagement means 3 may be extended (in a positive manner) or be recessed (in a negative manner), which means is adapted to interface corresponding engagement means of a surface element for friction increase that under operating conditions will approach and be placed adjacent to (with or without crushing pressure) the above described element 1.

Advantageously, the surface element 1 further comprises a predetermined number of clusters 4; included in these clusters 4 is the just mentioned engagement means and said clusters are defined by respective confining edges 4 a.

Clusters 4 are distributed on the lying portion 2 and are conveniently disposed according to a “matrix-like scheme” having ideal lines acting as virtual “rows” or “columns” disposed in any manner; for instance, in an embodiment given by way of example of the present invention this matrix-like scheme can contemplate an assembly of virtual straight lines on the intersection points of which clusters 4 (or at least the geometric centres of clusters 4) can be located.

The confining edges 4 a can have any geometric configuration, depending on current requirements; for instance, they can be of square or rectangular shape.

Still from the geometric point of view, the areas of the lying portion that are interposed between the different clusters (or that, in other words, are included between the confining edges 4 a and the perimetral edges 2 a) are generally smooth or more generally are not provided with the engagement means 3. According to a further feature of the present invention, in each of clusters 4 the engagement means 3 is disposed along directrices 4 b having at least one predetermined curvature (and consequently these directrices 4 b have a corresponding centre of curvature 4 c); advantageously, the centres of curvature 4 c of directrices 4 b belonging to clusters 4 that are separated and/or different from each other (or more generally disposed at positions different of the aforesaid matrix-like scheme) are not coincident with each other.

At this point the difference between the present invention and the previously illustrated state of the art is to be highlighted: in fact, due to the “geometric offsettings” between the directrices, ensured by misalignment/decoupling of the respective centres of curvature, any possible relative movement between the engagement means 3 of two elements 1 facing each other and in mutual contact is fully prevented.

In greater detail, even if two clusters 4 of two elements 1 geometrically defined by the same directrices are in mutual mechanical interference, relative slipping directions can be defined that can be subtended between the empty spaces between one directrix and the other; these possible relative slipping movements (intended both as translations and as rotations) are however prevented by the simultaneous presence of the other clusters that, having fully “misaligned” arrangements of the respective directrices, do not enable these displacements to take place.

Note that due to the main function of the invention hereabove illustrated, the interference/kinematic lock effect is given by the contact of the engagement means that in turn allows “three-dimensional” kinematic constraints to be established relative to the reference surfaces 2 b of the mutually facing surface elements 1.

In more detail as regards the present invention, it should be noted that the directrices 4 b belonging to a single cluster 4 can conveniently have a mutually concentric and/or parallel course; in this way they can define, at least merely from a geometric point of view, a geometric centre in common for all directrices belonging to a cluster (or also, depending on current requirements, for part of the directrices belonging to a given cluster) or an ideal line defined by the succession of centres 4 c.

Selection of the geometric shape of each set of directrices can be varied: for instance, the directrices 4 b can be made up of segments of a circle and/or segments of an ellipse and/or, more generally, segments of conics; in addition, should particular technical and/or aesthetic requirements be met, the directrices 4 b can comprise segments of lines having at least one flex and/or an undulated course (or even spiral-like lines and/or involuted curves of the epicycloidal or hypocycloidal type and so on).

Still from the geometrical/functional point of view, it is possible to see that the directrices 4 b of a single cluster 4 (ideally) define concave half-spaces and convex half-spaces on the reference surface 2 b; these concave and convex half-spaces are divided by the directrices 4 b themselves and are substantially “oriented” with a given “tracking” towards any point of the perimetral edges 2 a.

In order to give more or less powerful locking/kinematic interference capabilities to the invention, it is possible to suitably select the “orientation” of the concave/convex half-spaces belonging to different and separated clusters: for instance, as shown in FIG. 1, these half-spaces are defined by directrices 4 b such disposed as to appear as facing the same confining edge 2 a (for the sake of simplicity, it is possible to speak of convergence of the concave and convex half-spaces towards the same perimetral edge 2 a, even if they are not oriented towards a common centre).

Alternatively, as shown in FIG. 2, it is possible that directrices 4 b of different clusters 4 respectively define concave/convex half-spaces that face adjacent but not coincident perimetral edges 2 a, respectively. Yet, with reference to FIG. 4, directrices 4 b of different clusters 4 may define concave/convex half-spaces respectively, facing opposite perimetral edges 2 a.

From the construction point of view, said engagement means 3 can be made in different ways and/or using different materials, provided they are adapted to interfere with each other under conditions of mutual approach of at least two surface elements 1 according to the invention; for instance, the engagement means can comprise a plurality of substantially punctiform protrusions (for example of a globular, pyramidal or prismatic conformation or in the form of a truncated pyramid).

These protrusions extend transversely of the reference surface 2 b and are conveniently disposed sequentially along the directrices 4 b.

Alternatively, it is possible for the protrusions to have at all events a three-dimensional extension emerging from the reference surface 2 b, but with an important extension in length along the directrices 4 b; in some cases the protrusions may extend without a break on the directrices 4 b.

Falling within the present invention is also any object (such as a reusable and/or returnable package) which comprises a predetermined number of confining faces; advantageously, this object can be provided, on at least one of these confining faces, with a surface element for friction increase 1 according to that which has been hitherto described and will be hereinafter claimed.

Should the object be a returnable/reusable package, the confining faces of same can conveniently define a holding volume; this package therefore will be suitable for use with great advantage in handling operations based on clamping, due to generation of important friction forces on the lateral faces, by virtue of the presence of the invention.

The multiple packing of objects still falls within the scope of the present invention; said objects can be packages of the reusable and/or returnable type and will define an assembly comprising:

-   -   a predetermined number of objects disposed in a mutual         side-by-side-arrangement or mutual piling-up condition along a         (respectively) horizontal or vertical extension axis;     -   a predetermined number of abutment faces belonging to at least         two objects put adjacent to each other (these abutment faces are         therefore in a condition of mutual contact); and     -   friction increasing means acting at least between the aforesaid         abutment faces.

Advantageously, the above mentioned friction increasing means will comprise at least one, and preferably two (i.e. one for each abutment face) surface elements for friction increase 1 associated with at least one abutment face, and preferably with each of the abutment faces themselves.

As to accomplishment of the invention, the surface elements for friction increase findable in the multiple packing can be integrally formed in one and/or each of the abutment faces or, depending on current requirements, can consist of an autonomous body (that will practically have a laminar or “sheet-like” conformation), that in turn will be externally associated with one or each of the abutment faces.

The invention achieves important advantages.

In fact, due to the particular construction architecture of the surface element 1 (or, where required by the current requirements, of the object and/or the returnable/reusable package integrally carrying the surface element 1 on one of its faces), it is possible to generate an important sliding friction value even with low or zero contact pressures, and at the same time it is possible to eliminate any relative (translation or rotation) motion between the two faces in mutual contact; remarkably, the above listed effects are further amplified if the two contacting surfaces are respectively provided with surface elements 1 substantially identical with each other.

In addition, the possibility of moving the faces integrally provided with the surface element 1 close to and away from each other, or at all events the possibility of interposing one or two of these surface elements (that can be obtained as sheets/planar thin plates which are autonomous relative to the structures of the objects) between two faces of the objects themselves that can be mutually approached, greatly increases both the operating flexibility and the fields in which the invention can be used; for instance, these surface elements (in an “autonomous” planar form as shown in FIG. 6) can be used in retro-fitting in the handling operations by clamping of traditional (reusable and not) packages, that are not even provided with surface-friction increasing means.

Moreover, due to the easy definition and accomplishment of the different parts constituting the surface element according to the invention, it is possible to maintain low manufacturing costs, quick installation and setting times, high operating reliability and great simplicity of use and positioning; all that is obviously advantageous for production economy, amplification of the offered functionalities and improvement in the cost/profit ratio of the product or the process in which the invention is employed. 

1-11. (canceled)
 12. A surface element for friction increase associable with at least one surface of an object, said object being adapted to be moved close to and brought into contact with at least another surface of another object, said surface element (1) comprising: a lying portion (2) bounded by a predetermined number of perimetral edges (2 a) sequentially connected to each other and defining a reference surface (2 b); and engagement means (3) that can be extended and/or recessed relative to said reference surface (2 b) and which are suitable for interfacing with corresponding engagement means of a surface element for friction increase, characterised in that it further comprises a predetermined number of clusters (4) of said engagement means, said clusters being defined by respective confining edges (4 a) and being distributed on the lying portion (2), and characterised in that in each of said clusters (4) the engagement means (3) are disposed along directrices (4 b) having at least a predetermined curvature and a corresponding centre of curvature, centres of curvature (4 c) of directrices (4 b) belonging to clusters (4) separated from each other not being coincident therebetween.
 13. An element as claimed in claim 12, wherein directrices (4 b) belonging to a single cluster (4) have a mutually parallel and/or concentric course.
 14. An element as claimed in claim 12, wherein the directrices (4 b) comprise segments of a circle and/or segments of an ellipse and/or segments of conics.
 15. An element as claimed in claim 12, wherein the directrices (4 b) comprise segments of lines having at least one flex and/or an undulated course.
 16. An element as claimed in claim 12, wherein the directrices (4 b) of a single cluster (4) respectively define concave half-spaces and convex half-spaces on the reference surface (2 b), said concave and convex half-spaces being divided by the directrices (4 b) themselves.
 17. An element as claimed in claim 16, wherein concave and convex half-spaces defined by directrices (4 b) belonging to separated and distinct clusters (4) face the same perimetral edge (2 a).
 18. An element as claimed in claim 16, wherein concave or convex half-spaces defined by directrices (4 b) belonging to separated and distinct clusters (4) respectively face perimetral edges (2 a) that are adjacent but not coincident.
 19. An element as claimed in claim 16, wherein concave or convex half-spaces defined by directrices (4 b) belonging to separated and distinct clusters (4) face opposite perimetral edges (2 a).
 20. An element as claimed in claim 12, wherein the engagement means (3) comprises a plurality of punctiform protrusions having a globular or pyramidal or prismatic conformation or being in the form of a truncated pyramid.
 21. A reusable and/or returnable package comprising a predetermined number of confining faces adapted to define a holding volume, characterised in that at least one of said confining faces comprises a surface element for friction increase (1) as claimed in claim
 12. 22. Multiple packing of objects, said objects being packages of the reusable and/or returnable type, comprising: a predetermined number of objects disposed in a mutual side-by-side-arrangement or mutual piling-up condition along a horizontal or vertical extension axis; a predetermined number of abutment faces belonging to at least two of said objects placed adjacent to each other and in a condition of mutual contact; and friction increasing means acting at least between said pairs of abutment faces, characterised in that said friction increasing means comprises one or two of said surface elements for friction increase (1) as claimed in claim 12, said surface elements for friction increase (1) being associated with at least one of said abutment faces, said surface element/s for friction increase (1) being integrally obtained in said at least one of the abutment faces or being an autonomous body externally associated with one or each of the abutment faces. 